1. Field of the Invention
The present invention relates generally to hydraulics and more particularly to a fluid pressure energy translating device of the vane type designed to pump filtered seawater and use filtered seawater as the lubricating fluid. The seawater hydraulic vane type pump of the present invention is designed for underwater usage by providing pressure for actuating various operating components.
2. Description of the Prior Art
The design of a vane type fluid pressure energy translating device for underwater usage which pumps filtered seawater and uses filtered seawater as a lubricant presents a serious challenge to the designer because of the general corrosiveness of seawater on the precision made parts of such pumps. The poor lubricity of seawater and a much lower viscosity for seawater than for conventional oil hydraulic fluid contributes to the problem. The generally lower viscosity which seawater exhibits means that all design clearances must be an order of magnitude less than for prior art oil lubricated fluid pressure energy translating devices. In addition, potential leakage of an oil lubricant from the pump which might contaminate the underwater environment requires that no oils or greases be used.
A prior art energy translating device which utilized filtered pressurized seawater as the operating and lubricating fluid is disclosed in U.S. Pat. No. 4,376,620, entitled "Seawater Hydraulic Vane Type Motor" to John R. Colston. This vane type motor disclosed therein uses spring loaded rectangular shaped vanes having an arcuate outer end portion which serves as a sliding seal against a cam ring track. The vane members have side faces normal to the direction of rotor rotation, which side faces include grooves which extend along the entire opposed side face extent in a direction normal to the direction of rotation. A radially extending slot extends from the groove to the base of the vane to facilitate passage of pressurized seawater to the base of the vane to assist in urging the vane radially outward against the cam ring track. While this prior art energy translating device performs satisfactorily for its intended purpose as a power source for seawater hydraulic tools such as the band saw of U.S. Pat. No. 4,953,295, there are certain limitations in the design of this prior art energy translating device which prevent it from performing satisfactorily as a seawater pump.
Thus, it is an object of the present invention to provide an energy translating device which will function as an apparatus for pumping filtered seawater and use the filtered seawater as a lubricant.
It is a further object of the present invention to provide a seawater hydraulic vane type pump which is resistant to the corrosive effects of seawater.
It is still another object of the present invention to provide a lightweight, compact, highly efficient seawater hydraulic vane type pump.
These and other objects of the invention will become more apparent to those skilled in the art by reference to the detailed description of the present invention when viewed in light of the accompanying drawings.